Got a 73 1.7 just got back from shop fuel system should be all up to date just changed injectors and ECU unit(surprisingly died in both my 1.7s over a year or two) car has been running fine for a week. But when it warms up it starts losing its idle and ranges from 900-2000, going upppp, and downnn, and uppp, and downnn. Just started doing this. Curious if theres an easy fix to this. Cheers

It's called 'hunting'. Take a look at the stacked elbow. They can develop small cracks.

FYI, @Van B and have been stewarding some injector testing. We found that nearly half of even new injectors don’t spray well or do so terribly.
Did you have your new injectors tested before installing? Not ensuring this is your problem but could be important anyway.

it's hunting. If you just installed injectors look at them closely to see if one is cocked to the side bit. The gasket won't seal correctly creaking a vacuum leak which in turn causes "hunting". Also check all hoses, gasket on oil fill tower, bottom of air box for rust holes, TB butterfly shaft bushings. If you have difficulty locating the source remove & cap off every hose except the MPS. Then reconnect one hose at a time to see which point in the system has failed.

If anyone is interested ... no there werent any leaks.
The screw on the throttle body to adjust idle needed to be tweaked, car was idling to high and tricked computer to start hunting. Adjusted idle and car runs perfect. Thanks gor the responses!!